1. Field of the Invention
This invention relates to an enclosure for a power connector, e.g. an electrical connector, a hydraulic fluid connector or a compressed air line connector. The enclosure is used to prevent the power connector from being connected to a power source thereby preventing unauthorized use of power equipment, e.g. a television set, computer, air-operated drill, etc.
2. Description of the Prior Art
The prior art includes some patents disclosing protective enclosures for electrical connectors. U.S. Pat. No. 4,673,230 to H. Baumgart shows a protective enclosure for an electrical connector. A padlock is extended through apertures in the enclosure walls to retain the connector within the enclosure.
One difficulty with the arrangement of U.S. Pat. No. 4,673,230 is the fact that the enclosure cannot be installed onto the connector until the connector has first been disconnected from the associated power line or the power line has been disconnected from the associated appliance. Another difficulty concerns a possible inoperable relationship between the enclosure and padlock. Installation of the lock would be difficult or impossible, due to the physical impossibility of extending the U-shaped lock shackle through the apertures.
U.S. Pat. No. 4,488,764 to B. Pfenning shows a rectangular box-like enclosure for an electrical connector. A cover is openable to permit insertion and removal of the connector. The connector may be located within the box-like enclosure to prevent its unauthorized insertion into a source of electrical power and a key lock is built into the cover to prevent access to the connector. The connector may be operatively positioned outside the box-like enclosure, with the associated power line extending through the box-like enclosure, as shown in FIG. 10 of the patent.
One drawback with the arrangement of U.S. Pat.No. 4,488,764 is the fact that the box-like enclosure is separable from the electrical connector plug and associated power line. When the cover is removed from the enclosure, it is possible to lay the enclosure and cover aside where they can easily be forgotten or lost. It is advantageous to have the enclosure permanently connected to the power line, so that it cannot be mislaid or forgotten. The arrangement of U.S. Pat. No. 4,488,764 does not provide this feature.
Another disadvantage of the device shown in U.S. Pat. No. 4,488,764 is a relatively high manufacturing cost. A rectangular box of the type shown in the patent is manufactured out of sheet metal by stamping a blank from flat sheet stock, bending the blank at right angles to form the box sidewalls, and welding adjacent edges to the walls. Separate operations are required to form the cover and the structure for locking the cover on the enclosure.
It is believed that the protective enclosure will be more effective as a safety device if it is formed of a dielectric material, e.g. non-conductive plastic.
The lock-out enclosure of U.S. Pat. No. 4,488,764 also has the disadvantage of being unnecessarily large for its function. The square-shaped enclosure does not conform to the shape of the connector; therefore, there is considerable unused space within the enclosure. The lock arrangement used in U.S. Pat. No. 4,488,764 also contributes to an undesired bulkiness of the enclosure. As seen in FIG. 3 of the patent, the lock projects a considerable distance into the enclosure (approximately forty percent of the distance from the cover to the bottom wall of the enclosure). The disposition of the lock within the enclosure potentially interferes with the plug, such that the enclosure needs to be made larger than would otherwise be necessary.
The bulkiness of the enclosure disclosed in U.S. Pat. No. 4,488,764 is disadvantageous in that manufacturing costs are increased due to excessive raw material expense. The bulkiness of the enclosure is also disadvantageous in that the weight of the enclosure can inadvertently disconnect the connector from the associated outlet when the connector is removed from the enclosure and the enclosure remains attached to the power line.
U.S. Pat. No. 4,592,607 to R. Pejovic overcomes some of the disadvantages of the enclosure shown in U.S. Pat. No. 4,488,764. Pejovic discloses an enclosure formed by two rectangular hollow half-sections. The rectangular shape of this enclosure does not conform to the shape of the associated connector and like the enclosure taught by Pfenning is not very space efficient. Further, Pejovic's enclosure is completely separable from the power line and, hence, susceptible to being mislaid, lost, stolen, or otherwise not available when needed.
U.S. Pat. No. 4,721,475 to Burke, Jr. discloses a tubular enclosure enclosing both a male connector and female connector. The tubular shape shown in this patent has a relatively good space utilization because there is relatively little unused space within the enclosure. However, the enclosure taught by Burke, Jr. was designed to house both the male and the female connector in connected and disconnected states; therefore, the enclosure is relatively large in an absolute sense. Also, the structure taught by Burke, Jr. is designed so that the connectors are fixedly attached to the enclosure components. The connectors must be disconnected from their associated power lines 12 and 14 before they can be attached to the respective enclosure components.